Today's mediums and psychic detectives are nothing new – people have been claiming the ability to see the future, speak with the dead or read minds since antiquity. Scientific experiments testing for evidence of paranormal abilities are a relatively modern phenomenon, however. Has science ever produced verifiable evidence of ESP?

Organized research into ESP and related phenomena began in the late 1800s, coinciding with the explosion of spiritualism (contact with spirits of the dead, usually by mediums) in the U.S. and Europe. In 1882, the Society for Psychical Research was formed. This London-based group performed the typical paranormal research of that era, which consisted primarily of testing self-proclaimed mediums under controlled conditions and collecting anecdotes of "spontaneous" ESP.

A similar effort was undertaken in the U.S. by the Seybert Commission. Henry Seybert was a huge fan of spiritualism, and he left a pile of money to the University of Pennsylvania so they could form a commission and prove how awesome and true spiritualism was. They investigated several phenomena typically performed by mediums of the day. In the case of slate writing (ghostly writings on seemingly inaccessible slates held in the medium's lap), they found nothing but fraud. Spirit photography they found so ludicrous they didn't even bother testing it.

The Seybert Commission developed an ingenious method of testing mediums who claimed to produce ghostly rappings and other loud noises. Many mediums were female, and the decorum of the day made it difficult for the commission to directly monitor all the parts of a woman's body to make sure she wasn't making the rapping sounds herself. Instead, the commission let the medium do her thing. They would then intermittently make their own rapping noises, indistinguishable from those made by the medium. A startled medium meant she wasn't expecting to hear noises she hadn't made herself.

The commission ultimately declared that every tested instance of psychic ability was in fact fraudulent. Luckily, Henry Seybert was unable to communicate his displeasure with them from beyond the grave.

Some of the earliest laboratory experiments into ESP were conducted by John Edgar Coover at Stanford University, starting in 1911. Coover used wooden blocks with numbers on them, which he called Lotto Blocks. The experimenter sat behind the subject, drew a block from a bag, and either focused on visualizing the number or didn't. The subject tried to guess the number. Coover found that the results did not differ appreciably from random chance in either condition, and in fact in several trials the subjects did better when the experimenter was not thinking about the number.

Coover's writings on the subject were indicative of the zeitgeist for paranormal research at the time:

"The research is undertaken with a zeal for Truth, and is projected and controlled with an anxiety for the strength of the bridge it is building, which must bear the strain of the passage of men of learning, men of influence, men of science, from the shore of accepted knowledge to the island of the not-yet-recognized."

A landmark in ESP research came in the 1930s, when Duke University opened a lab specifically for the study of the paranormal. Karl Zener and Joseph B. Rhine conducted the most famous experiments, using special cards designed by Zener. These white cards depicting either a circle, square, plus, star or wavy lines are today known as Zener cards. They were developed because standard playing cards presented a series of problems and added complexity when used in experiments. Zener cards made it much easier to determine probabilities and to control the distribution of cards within a given set of tests.

At first, Rhine found subjects with incredible abilities, able to guess the symbol on the card far more often than chance would predict. Then they noticed that people could see the symbols through the thin paper of the cards. This would be a recurring problem throughout the history of ESP research: poor experimental design. Over the years, Rhine found several subjects he claimed showed paranormal abilities, but his results could not be duplicated by other researchers. Critics claimed his subjects were cheating and that Rhine simply didn't report many tests that came up negative for ESP.

Rhine established the Parapsychological Association in 1957; it was accepted into the American Association for the Advancement of Science (AAAS) 12 years later, which gave parapsychology an aspect of respectability. A number of journals devoted to paranormal research also sprung up during this period, including the Journal of Parapsychology and the Journal of the American Society for Psychical Research. This brings up another recurring problem with scientific psychic research: virtually all papers in the field are published in journals exclusive to paranormal research. To the extent that they are peer-reviewed, those peers are also engaged in paranormal research, and the journals are not considered as rigorous or prestigious as more mainstream peer-reviewed journals.

This seemed to open the floodgates, as paranormal investigation societies proliferated throughout the 1970s. The Institute of Noetic Sciences, Academy of Parapsychology and Medicine, the International Kirlian Research Association, the Institute of Parascience, and the Princeton Engineering Anomalies Research Laboratory were all formed during this period.

The Princeton lab is a good example of how these groups tended to rise and fall. Founded by Robert G. Jahn in 1979, it was funded entirely by private donations and published almost all of its papers in its own journal, the Journal of the Society for Scientific Exploration. Professors at Princeton (none of which joined the lab or conducted research there) tended to view it as an embarrassment, but generally supported Jahn's academic freedom to pursue his research as long as he could get his own funding. Still, serious journals refused their studies. According to the New York Times, "One editor famously told Dr. Jahn that he would consider a paper ‘if you can telepathically communicate it to me.'" (This may be apocryphal – I was unable to find the original source of the quote).

A typical PEAR lab experiment used a random number generator that would crank out numbers close to 100, either just above or just below. Subjects sat at the machine and thought, "High" or "Low" to see if they could shift the machine's results away from pure chance, even by slight amounts. In 2007, Jahn finally gave up and shut down the lab. The results? Over a huge number of tests, Jahn claimed humans could affect probability by a few hundredths of a percentage point. He felt this proved that mass positive thought by humans could create measurable change in the world.

Psychic research in the last decade or so has taken a decidedly more skeptical approach, at least where official university sanctioned research is concerned. Papers showing evidence of ESP mostly remain confined in the "psychic ghetto" of journals expressly devoted to the paranormal. That makes the exceptions particularly notable. Case in point: Daryl Bem's studies on precognition were recently published in the Journal of Personality and Social Psychology. That journal is most certainly not a fringe rag – it's one of the more highly regarded psychology journals.

One of Bem's experiments showed that subjects could remember things that hadn't happened yet. In a standard memory experiment, the subject sees a list of words, then is asked to type half of them. Later, when asked to recall as many words as possible from the full list, the words that were typed are remembered much more frequently. Bem started with the list as usual, but then went right to the, "remember as many of those words as you can" step. Only later was the subject asked to type half of the words on the list. Since the subjects "remembered" the words they would later type better than the words they would later not type, Bem theorized that future events can somehow influence the present.

There are certainly critics who claim the paper should never have made it through the Journal of Personality and Social Psychology's peer review. Bem's statistical analysis is the basis for most criticisms, but in any case, the results have yet to be duplicated by other researchers.

That leaves us with more than 100 years of scientific examination of ESP and not much to show for it.

Sources:

Carey, Benedict. "A Princeton Lab on ESP Plans to Close Its Doors." New York Times, Feb. 10, 2007.